// SPDX-FileCopyrightText: Copyright (c) 2014-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: BSD-3-Clause
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#include "NvFlowShader.hlsli"

#include "EmitterParams.h"

ConstantBuffer<EmitterNanoVdbCS_Params> gParams;

StructuredBuffer<uint> gTable;
Texture3D<float4> valueIn;
RWTexture3D<float4> valueOut;

[numthreads(128, 1, 1)]
void main(uint3 dispatchThreadID : SV_DispatchThreadID, uint3 groupID : SV_GroupID)
{
    int3 threadIdx = NvFlowComputeThreadIdx(gParams.table, dispatchThreadID.x);
    uint locationIdx = groupID.y + gParams.blockIdxOffset;

    int4 location = int4(
        int(locationIdx % gParams.locationExtent.x) + gParams.locationOffset.x,
        int((locationIdx / gParams.locationExtent.x) % gParams.locationExtent.y) + gParams.locationOffset.y,
        int(locationIdx / (gParams.locationExtent.x * gParams.locationExtent.y)) + gParams.locationOffset.z,
        gParams.locationOffset.w
    );

    uint blockIdx = NvFlowLocationToBlockIdx(gTable, gParams.table, location);

    if (blockIdx >= gParams.table.numLocations)
    {
        return;
    }

    int3 vidx = (location.xyz << gParams.table.blockDimBits) + threadIdx;
    float3 vidxf = float3(vidx) + float3(0.5f, 0.5f, 0.5f);
    float3 worldPos = gParams.vidxToWorld * vidxf;

    float4 localPos = mul(float4(worldPos, 1.f), gParams.worldToLocal);
    float3 localPosTranslated = localPos.xyz - gParams.position;

    float opacity = 1.f;
    if (abs(localPosTranslated.x) < gParams.halfSize.x &&
        abs(localPosTranslated.y) < gParams.halfSize.y &&
        abs(localPosTranslated.z) < gParams.halfSize.z)
    {
        int3 tempIdx = threadIdx + int3(
            (int(groupID.y & 15) << int(gParams.table.blockDimBits.x)),
            ((int(groupID.y >> 4u) & 15) << int(gParams.table.blockDimBits.y)),
            ((int(groupID.y >> 8u) & 15) << int(gParams.table.blockDimBits.z))
            );
        float4 value = valueIn[tempIdx];

        NvFlowLocalWrite4f(valueOut, gTable, gParams.table, blockIdx, threadIdx, value);
    }
}
